Memphis SRX1200.1V Instruction Manual page 6

Speaker Connections Continued
SRX250.1V // SRX500.1V // SRX750.1V // SRX1200.1V
The RCA jacks marked Low Input should be connected to the low level outputs of your source unit or signal processor.
High level(speaker level) inputs are provided as well.
(SRX1200.1V - 1 STABLE)